How many IPs can be put on a single NIC?

I've got an FTP server that has a bunch of FTP sites on seperate IPs on the same card. The computer is running windows 2003 server and i'm wondering how many IPs can be put onto a single card before it either:

A. won't take anymore
B. Starts affecting performance.. i.e. memory

Obviously if there is no limit in windows then i should be able to put up to a full class C set of IPs on there, but hopefully long before then i'd put in another card or server.

Just curious...

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mikeleebrlaConnect With a Mentor Commented:
even if they are for different customers with mulitple users you still dont need a seperate IP for each customer.. just set thier home drives approprately... for example


company1user1 would start out at the "company1"directory
company2user1 would start out at the "company2" directory

that way company1 would never see anything referencing company2 and visa versa

it was an interesting question so I did a bit of research and found a post where someone with some serious hardware (quad xeon, 10gb ram, load balanced server nics) does not recommend to go over 40-50 IPs per interface (not cheap desktop NICs, but server grade ones). Performace - if you'll encounter some serious traffic and start to slow down then upgrage.
i thought this was an interesting question,,,the best solution would be to let the firewall/router point all the IPs to one statically assigned IP on the NIC, rather than have the NIC have 30-50 or whatever IPs statically assigned to it by the 2003 OS.  routers/firewalls are designed for this, server nics and the OS aren't really.
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tonkajeep34Author Commented:
Yeah that's what i thought... tried to call MS to ask their recommendation and they want $245....

I've been doing host headers for the websites and that does work well... but for FTP sites i've not been able to do that. Hints? Some of the smaller ones (single user)i've been using IIS6 isolation and that works well, but i have some other sites that need multiple isolated users themselves.

I've got a lot of LOW volume ftp sites about 45 on a single NIC at the moment and everything seems fine but i've been trying to plan out for the next year and i'm thinking i'll need to just add some more NICs/Servers in.
why not just have your FTP users all ftp into ONE IP and then have thier "home" directory set based upon there login name? Or just set appropriate NTFS permissions so users can only access what you want them to rather than having totally seperate FTP sites for each user with their own IP?
tonkajeep34Author Commented:
For the most part each site is a different customer with multiple users. The single user customers are setup exactly like you suggest all going to a single ftp site.
tonkajeep34Author Commented:
Hmmm... i'll have to try that. i'm not sure how it'll work with the isolation in IIS6 though. it like is's LocalUser directory/user structure

I'm sure it'd work if i didn't do the isolation...

Right now the traffic is so light and the hardware is pretty beafy.. Dell 2650 with dual xeon 2.8 2gb ram 10k scsi and that is it's sole purpose in life so i think it'll be ok for now. If the traffic goes way up or we suddenly add a bunch more clients i'll have to watch it closer.

Well.... I had a look into that matter . So i got this .

Only one IP can be assigned to 1 NIC , weather may be static or DHCP. And as per ur problem , you can use aliasing to use many names and/or IP address for the same NIC. I think its the best option, and if you are using Linux , then check /etc/resolve.conf and /etc/named.conf files.

Best of luck.

"Only one IP can be assigned to 1 NIC" this isn't true at all,,, all you have to do is press the advanced button and you can assign multiple IPs to a nic,,,, why are you talking about linux??,, he is using windows 2003
support mikeleebrla 100% !!!  that was a nonsense statement by sachin_21_leo
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